1. Field of the Invention
The present invention relates to a method and apparatus for detecting a touch point of an object.
2. Description of the Related Art
There are a variety of methods to deliver or obtain information by directly touching an information medium. Touch panel displays are a known useful technology and have been used to deliver or obtain such information. For example, touch screen panels incorporating LCD technology have been developed. The touch screen panel incorporating LCD technology may also be applied not only to the LCD field but also to other suitable display fields. In particular, this technology may be applied to organic light emitting diodes (OLEDs) that are regarded as a next generation display technology.
In an optical sensor type touch panel display device, an optical sensor is arranged in each pixel so that input of information on a screen utilizing light is possible. In the optical sensor type touch panel display device, for example, a photodiode is used as the optical sensor and a capacitor is connected to the photodiode of each pixel. Data of an image is generated by changing the amount of charges of the capacitor according to a change in the amount of light received by the photodiode, and detecting voltages at the opposite ends of the capacitor. A display device having a function as a touch panel or a digitizer has been suggested as a possible application of the optical sensor type touch panel display device. The touch panel function enables input of information by detecting the shadow of an object, for example, a finger, projected onto a screen. Although the input information is recognized through a variety of image recognition algorithms, such image recognition algorithm are complex, and the large amount of calculations needed to operate such complex image recognition algorithms may impose a heavy burden on hardware.